Tesla

[Morris Minor]

Wow - muchos Teslas in the Bay Area (visiting to see my kids & granddaughter.)  Model Y is the the best seller in CA, Model 3 is #2.
Also saw my first Bolt EUV - nice.

[Morris Minor]

They're rolling out FSD Beta 11 in NA... to anyone who bought the option & requests it. So it's going to be a lot more than the current 100,000 testers.
It's single stack - merging FSD's city driving & Autopilot's highway driving into one. I wonder if they'll deprecate the Autopilot software stack completely & just make it a de-contented FSD. Probably not an option on Hardware 2 but it would make sense on HW3.

https://insideevs.com/news/622776/tesla-fsd-beta-11-release-notes/

[afty]

Apparently the 12V battery in my Model 3 is dying. I got this notification on the screen the other day.

Interestingly most EVs still have a normal 12V lead acid battery to power accessories. I guess it's so that they can use off the shelf accessories designed for 12V power. It's nice that I get this notification before the battery dies and strands me somewhere.

[Morris Minor]

Tesla Semi was launched last night. I can't think of a business more conservative & resistant to disruption than the long haul trucking industry. Let the coal rolling begin.

[giant_mtb]

"Dec 1 (Reuters) - Tesla Inc (TSLA.O) Chief Executive Elon Musk delivered the company's first heavy-duty Semi on Thursday to PepsiCo (PEP.O) without offering updated forecasts for the truck's pricing, production plans or how much cargo it could haul."

What a launch!

[MrH]

Tesla Semi was launched last night. I can't think of a business more conservative & resistant to disruption than the long haul trucking industry. Let the coal rolling begin.

"Launched"

[Laconian]

Apparently the 12V battery in my Model 3 is dying. I got this notification on the screen the other day.

Interestingly most EVs still have a normal 12V lead acid battery to power accessories. I guess it's so that they can use off the shelf accessories designed for 12V power. It's nice that I get this notification before the battery dies and strands me somewhere.

Isn't it mostly to bootstrap the BMS? I can't imagine it has to deal with big loads. The small electronics are 12V DC but I would think the DC-DC converter hooked up to the traction battery would be doing most of the gruntwork.

[GoCougs]

Since EVs don't have alternators (AFAIK), there's already a 400 VDC (or 800 VDC) to 12 VDC converter somewheres in order to charge/top off the 12V lead acid battery. So, here are my guesses:

Redundancy - microcontrollers tend to not like to be completely powered off, and an EV I'm also guessing has WAY more and WAY more complicated ECUs than an ICE-powered vehicle

Legacy automotive circuit design - DC circuit functionality can be more than just voltage and current, attributes such as capacitance and resistance can be factors too (e.g., 12 VDC from a battery may not look the same as 12 VDC from a DC-to-DC converter to a particular circuit)

Protection - a battery will act as a buffer for intermittent spikes and drop-outs from a DC-to-DC converter or battery pack (which may happen during charging or hard accel or ?)

[afty]

I'm not sure. I can tell you it disabled my heated seats and built-in dash cam until I replaced the battery. I've seen graphs of the charge/discharge behavior and it looks pretty hard on the battery. I think this is why it didn't last too long (3.5 years in mild CA weather).

Here's an older article op the looks at the 12V battery behavior in a Model S: https://www.sevarg.net/2016/10/30/tesla-model-s-12v-battery-analysis/

[Morris Minor]

There's a rumor flying round that Tesla is planning to cut production in Shanghai this month - no reasons given yet. But lockdown nonsense / soft demand come to mind.
Just a rumor.

I have always been wary of Tesla having too many eggs in the China basket.

Apple's looking to reduce its dependency... it's looking to move some of its production to Vietnam & India.

[Laconian]

Since EVs don't have alternators (AFAIK), there's already a 400 VDC (or 800 VDC) to 12 VDC converter somewheres in order to charge/top off the 12V lead acid battery. So, here are my guesses:

Redundancy - microcontrollers tend to not like to be completely powered off, and an EV I'm also guessing has WAY more and WAY more complicated ECUs than an ICE-powered vehicle

Legacy automotive circuit design - DC circuit functionality can be more than just voltage and current, attributes such as capacitance and resistance can be factors too (e.g., 12 VDC from a battery may not look the same as 12 VDC from a DC-to-DC converter to a particular circuit)

Protection - a battery will act as a buffer for intermittent spikes and drop-outs from a DC-to-DC converter or battery pack (which may happen during charging or hard accel or ?)

I don't know if dump loads are as much a thing for DC-DC converters as they are for alternators, but those arguments seem plausible.
The DC-DC converter is seriously beefy. The one in the Model S can output 200A at 12V.

[afty]

AIUI early Tesla Roadsters did not have a 12V battery.  This article says they were added because

The reason for a separate 12v battery is to power critical systems in the event of a high-voltage battery disconnect. This keeps key systems operational such as emergency blinkers, airbags, seatbelt pre-tensioners, brake booster, and a host of other systems. The high-voltage battery might be disconnected due to several rare events – such as a high-impact crash, internal main battery pack problems such as some types of cell failures, a contactor failure, and a few other unlikely situations.

Many parts of the Tesla vehicles today are powered by the 12v system, including:

• All lights, such as headlights, turn lights, fog lights, taillights, backup lights, license plate, and interior lights
  
• LCD Display –Instrument Cluster (S/X) and the main display
  
• The MCU and many modules with processors
  
• Non-traction motors, such as windows, liftgate (S/X), wipers, washer fluid, seat motors, side mirror adjusts, sunroof (if equipped) charge port door, steering assist, fans, coolant valves, and coolant pumps
  
• An audio system including tuners, antenna amplifiers, and audio amplifiers
  
• Safety systems, such as airbags, brake booster, and seatbelt pre-tensioners
  
• Autopilot systems including cameras, sensors, and radar (if equipped)
  
• Heated items, if equipped such as seats, steering wheel, washer nozzle, side mirrors, rear defrost, and camera heaters.
  
• Other items like the alarm, mirror dimmers, USB ports, horn, HomeLink, air suspension (if equipped), and various latches (doors, trunk, frunk, glovebox)
  
• High-voltage battery pack contactors
  

Only a few items are directly powered by the high-voltage battery pack. This includes the traction motor(s), the a/c heat pump, and the DC to DC converter for 12v power and charging the 12v battery.

[Laconian]

Yeah, I could see why a dumb lead acid battery could be useful. There are more failure modes on lithium batteries and especially BMSes that will cause them to just FYA completely.

[Morris Minor]

12 V system is like a plane's APU.
"Both engines are out Cap'n, would ye like me to fire up the APU?
"Make it so #1. We may end up in the Hudson."

[afty]

The Tesla Semi completed a 500-mile drive from the Fremont, CA, factory in the Bay area to San Diego.  This battery percentage vs. distance chart with elevation overlaid is pretty cool:



Note the Grapevine section -- this a mountain that you climb about 100 miles outside of L.A.  It's a pretty steep grade, and you can see that in how quickly the battery percentage drops while it's going up. The neat part is that on the downhill side, the battery percentage actually goes up as the Semi recaptures some of that kinetic energy instead of turning it into heat like an ICE vehicle. 

I've driven this route several times in my Model 3, and it pretty closely mirrors my experience except that I have to charge twice, typically at Kettleman City (arrive around 30%) and then somewhere in L.A.

[Morris Minor]

So you would not want to be charging up to full just before beginning a descent. There's no regen happening if you're already maxed out.

The other thought I'm having is that a standard shipping container is pretty much a disaster in terms of aerodynamics, as is the trailer part of a tractor trailer.

It'll be interesting to see where this goes.

[Laconian]

Really cool. Imagine all that energy being stored in a battery instead of being released as earsplitting jake brake noise. Semis tend to avoid using their brakes on long descents.

[Soup DeVille]

Really cool. Imagine all that energy being stored in a battery instead of being released as earsplitting jake brake noise. Semis tend to avoid using their brakes on long descents.

For good reason too.

Which is one reason why a hybrid setup for semis would be a better choice than a full-electric one.

[Laconian]

For good reason too.

Which is one reason why a hybrid setup for semis would be a better choice than a full-electric one.

Could you have a mechanical device which only drives an air compressor as a failsafe? Like a jake brake without an engine.

[Soup DeVille]

Could you have a mechanical device which only drives an air compressor as a failsafe? Like a jake brake without an engine.

Probably. You could also have braking resistors to burn off the extra energy.

[Laconian]

Probably. You could also have braking resistors to burn off the extra energy.

That would require a number of electrical systems to work properly. Maybe you could have multiple levels of mitigation.

[Morris Minor]

There's a rumor flying round that Tesla is planning to cut production in Shanghai this month - no reasons given yet. But lockdown nonsense / soft demand come to mind.
Just a rumor.

I have always been wary of Tesla having too many eggs in the China basket.

Apple's looking to reduce its dependency... it's looking to move some of its production to Vietnam & India.

And here it is...
https://www.reuters.com/business/autos-transportation/tesla-cuts-dec-model-y-output-shanghai-plant-by-over-20-versus-nov-sources-2022-12-05/

[GoCougs]

That would require a number of electrical systems to work properly. Maybe you could have multiple levels of mitigation.

And the resistors would be ginormous, even if fan cooled - not practical on a moving vehicle probably.

Commercial trucking is a ginormous source of air and noise pollution, no doubt, and akin to forklifts or golf carts, much more amenable to electrification (highly curated usage - mitigate if not eliminate "refueling" problems). The problem, just like with retail EV vehicles, is cost. I have a friend is an exec at a drayage firm in CA, and they have to go electric to service the ports. Thing is the EV trucks (they're going Volvo) are about double the cost and have less range. Various governmental entities are offering ginormous incentives but that's not sustainable. An electrified EV trucking industry will catastrophically impact the cost of goods. All in all, just as with retail EVs, it's not sustainable on any sort of scale.

[Morris Minor]

I wonder what PepsiCo will be hauling.
Cheetos & Salt 'n' Vinegar crisps?
Or the fizzy drinks?

[AutobahnSHO]

I SERIOUSLY don't understand why they don't do some hybrid magic in the semis.

From what I've read, most hybrids have "just enough" battery capacity to charge up during braking then get the vehicle back up to speed. That would be huge for "city" trucks. (not as efficient for interstate to haul extra dead weight)...

[Laconian]

Back of the napkin analysis with some good high school physics.
https://www.youtube.com/watch?v=Uv44W7xa4IU

The benefit of diesel is that there are tens of thousands of places where you can fill up. Whereas with Tesla you have only one vendor that can replenish your vehicle. That's a lot of leverage to give a single company.

[Laconian]

Radar is back to Teslas. Sucks to be the folks who bought cars during the Tesla Vision-only phase.
https://electrek.co/2022/12/06/tesla-radar-car-next-month-self-driving-suite-concerns/

It's good for public health that autonomous cars are finally getting real sensors back, but after the anti-radar PR blitz I have to say that the flip-flopping is pretty gross.

[Laconian]

https://twitter.com/torynski/status/1600968583055826944

Analysis of Tesla semi from an actual semi driver.

[giant_mtb]

"it's a rich boy's toy"

A truck designed by non-truckers. The world finds it amazing because it looks futuristic and Elon Musk is a goofy genius. Meanwhile it was delivered years late and the real truck manufacturers have already been in the EV semi game for years.

[Soup DeVille]

https://twitter.com/torynski/status/1600968583055826944

Analysis of Tesla semi from an actual semi driver.

i can't disagree with any of that.